Concrete Roads
and Their Construction

IN INDUSTRIAL WORKS AND MILITARY CAMPS 77 laid in the spring of 1918. The length which has been concreted is about 800 ft., and the width of the road is 18 ft. between the kerbs. Concrete kerbing, 6 in. thick, was first moulded in situ, the mixture used being 3 of sand to 1 of cement. No reinforce- ment was used for this kerbing, but to allow for expansion joints were formed with deal strips | in. thick, spaced every 12 ft. The concrete of the road was 6 in. in thickness, and con- sisted of a bottom 4 in. of 6 : 1 mixture, and a finishing surface 2 in. thick of 3 : 1. It was reinforced throughout with metal mesh, placed as nearly as possible 3 in. above the bottom—i.e., in the centre of the concrete. In order to reduce the number of joints (which are a source of weakness in concrete roads), each day’s work was done continuously in one bay, and sufficient space was left between one day’s work and the next to allow of the intervening bay being put in afterwards when those on each side were set. One thickness of tarred paper was placed against the ends of the completed bays before the intervening bay was filled in. The reinforcement was placed so that it stopped 2 in. from the end of each bay, and also 2 in. from the kerbing on each side, in order to ensure that it was protected by concrete from any risk of corrosion. The number of vehicles passing over the road is not very great, but they are of all classes, including large motor lorries and steel- shod steam wagons. The illustration Fig. 50 shows this road after completion. The whole road is on a gradient from one end to the other, but the gradient varies throughout its length. A cross-fall to both kerbs of 1 in 50 was provided. Latest Reports, November, 1920.—According to a report from the chief engineer of the above Company, Mr. D. T. Maclvor, and a later report by an independent observer, the road has been in use two years and is in as good condition as when first opened. The method adopted for constructing this road, viz., by alter- nate bays, has quite justified itself, and has demonstrated that it is both unnecessary and undesirable to provide “ expansion ” joints in a reinforced concrete road. It is understood that the Empire Paper Mills Company is highly pleased with this road, as, prior to its construction, great trouble and expense had been experienced in keeping up the macadam roadway, whereas the concrete road has cost nothing for upkeep, and is not affected by the state of the weather.